1. Field of the Invention
The present invention relates to an electronic component, and more particularly, to a surface mount resistor for current sensing.
2. Description of Prior Art
Following continuous progress of electronic circuit technology, stability requirement of resistance value of resistor has been increased day by day. Some performances of traditional chip resistor, such as temperature coefficient of resistance (TCR), have gradually been unable to satisfy the requirement of high stability, thus, causing its limitation in terms of application.
In order to promote thermal stability of resistor, Taiwan Patent Publication No. 200830333 and 200830334 have proposed a current sensing resistor, in which a heat-dissipation body with high performance is formed on a surface of a resistor body to dissipate the heat generated therefrom, such that the object of promoting the operational power of the current sensing resistor is achieved.
The resistor body and the heat-dissipation body with high performance are respectively formed by a stamping process and then combined by a pressing process or an adhering process. However, during the stamping process, surfaces of the resistor body and the heat-dissipation body will generate deckle edges or protrusions, which probably penetrate the pressed or adhesive layer (its thickness is about 30 μm) during the combination of the resistor body and the heat-dissipation body, causing a short circuit, because of the contact between the resistor body and the heat-dissipation body, so the resistance value of the resistor can't fulfill preset requirement. Furthermore, since the current sensing resistor adopts two rectangular heat-dissipation bodies, which are symmetrical to two sides of the resistor body, only heat at two sides of the resistor body can be carried away, while the heat at the central portion with higher temperature can't be dissipated. This kind of design has imposed a great limitation on carrying away the heat generated in resistor body, which limits the promotion of the operational power thereof.